alics Blogs

1 Introduction of mechanical drawing and CATIA software

Mechanical drafting is the discipline of using drawings to represent the exact structural shape, size, working principle and technical requirements of machinery. The drawing consists of graphics, symbols, words and figures, etc. It is a technical document that expresses design intent and manufacturing requirements as well as communicates experience, and is often referred to as the language of the engineering community.

In addition mechanical drawing is also one of the basic compulsory courses offered by mechanical and related majors in engineering higher education institutions.

CATIA is a CAD/CAM drawing software created by the French company Dassault Aviation. It encompasses the entire process of mechanical product manufacturing and can help manufacturers design their future products through modeling and reduce development costs by not only shortening the product development cycle but also improving design quality through the entire industrial design process including specific design, analysis, simulation, assembly to maintenance. It is currently used in many fields, such as aviation, aerospace, mechanical, electronic, automotive, marine, electrical, etc.

2 Mechanical Drawing and CATIA Experimental Teaching Status

Mechanical drawing and CATIA experiment are two relatively independent courses, mechanical drawing is a professional basic theory course, usually in the first year for mechanical students, the teaching task of this course is to train students to quickly read and draw mechanical drawings, the ability to analyze and explain the simple three-dimensional modeling entity and the ability to think logically and spatially about the product assembly and component location relationship.

In the conventional mechanical drawing theory teaching, teachers need to use multimedia courseware, teaching physical models while demonstrating to help students understand what they have learned. The entire course lacks interaction between teachers and students, and some students even play with their cell phones or sleep because of the tedium, making it difficult for them to concentrate on the lessons and to establish spatial thinking to achieve the proper purpose of classroom teaching.

CATIA experimental teaching, opened in the junior year, the experimental class relies on the mechanical CAD/CAM theory class and opened. From the surface, these two courses are relatively independent, taught by different teachers, and they are held one year apart, so that the two closely related courses are separated, and their teaching effect is not very satisfactory. In order to change? This situation, the key lies in the integration of the curriculum, in theoretical teaching at the same time to add practical elements, the effective combination of the two.

3 The integration of mechanical drawing teaching and CATIA experimental teaching

Teachers in the mechanical drawing classroom in addition to the use of model demonstration, but also in the multimedia installed CATIA software, and in the classroom teaching gradually infiltrate the concept of three-dimensional modeling, guide students to virtual entities through the three-dimensional mode multi-angle, multi-directional display.

In addition, adding the study of CATIA experiments to the teaching of mechanical drawing theory, with its part design function, product assembly function and motion simulation function, can help students quickly familiarize themselves with 3D spatial shapes, which not only enriches the teaching content, stimulates students’ interest in learning, but also cultivates their spatial imagination.

Benefits of adding CATIA experiments.

(1) After students learn CATIA software and become proficient in using command icons, they can learn it on their own after class, while in the process of operation and use, they can enhance their understanding and application of drafting knowledge by learning from classroom knowledge and creating different 3D entities in the experiment, so that theory and experiment complement each other and lay a good foundation for making engineering documents in the future.

(2) For first-year students, it is very useful to learn the part design module, product design and engineering drawing module in CATIA software, these modules can generate two-dimensional view by stretching the entity for three-dimensional modeling, but also three-dimensional entities by generating engineering drawings to obtain the multiple two-dimensional views we need, learners can intuitively see the two-dimensional plane and three-dimensional entity conversion each other process, to improve the learning effect of the course plays a great role.

(3) CATIA software has the function of component assembly and curved surface design, students can innovate and design different products by themselves to improve the learning interest of mechanical drawing.

4 CATIA software in the application of mechanical drawing teaching

4.1 3D modeling of parts

The course of mechanical drawing needs to establish a certain abstract thinking, and for the freshman students, the establishment of this thinking will be more difficult, the conventional teaching methods are teachers with a lot of drawing models in class, while demonstrating and explaining, in order to help students learn to understand, but the model teaching some rigid, students are easy to pay attention to inattentiveness, if the use of three-dimensional software to assist the explanation, students will be very interested If we use 3D software to assist in teaching, students will be very interested.

CATIA software is based on sketching, creating basic features to modify the features to create the shape. ` These feature commands are to add material, such as stretching, rotating body, reinforcement, etc., and some are to remove part of the material from the existing material, such as digging grooves, punching holes, etc.. Also on the basis of this can be trimmed and shape transformation, such as chamfering, corner cutting, translation, symmetry, mirroring, etc. These commands can quickly create three-dimensional entities, that is, parts.

At the same time, through the demonstration of zooming in, zooming out, and flipping of parts, students’ awareness of the conversion from two-dimensional to three-dimensional space is enhanced and their understanding of textbook knowledge is strengthened.

4.2 Component Assembly

Part assembly is the most basic module of CATIA, and it is also the module that makes CATIA the leader from other drawing software. It has the main functions of creating new assemblies, assembling specific assembly parts or multiple parts into an assembly, and developing assembly relationships between each part.

Products (assemblies) are assembled from different parts in a certain order and have a complex structure, and their assembly drawings are difficult to read, so combining the knowledge of CATIA can improve the teaching effect.

CATIA has the functions of creating parts, changing the position of parts and creating constraints. By changing the position of parts, each part can be assembled according to the assembly order of the assembly diagram and the position relationship between parts by changing the position of parts, intelligent movement, face-to-face overlap, face-to-face contact, two plane offset, two surface angle constraints, etc. Also, the assembly can be decomposed by using the decomposition command, so that students have a more profound understanding.

4.3 Generate engineering drawings

Based on the 3D model, CATIA software can map the created 3D shapes into 2D views, dimension and tolerance markings, add surface roughness symbols, welding symbols, etc., add part numbers, title bars, text comments and detail tables in the lower right corner, and save the unique drawing file.

The engineering drawings generated in this way can help first-year students understand the interconversion of 3D modeling and 2D engineering drawings as soon as possible, and can also check whether the views they draw are correct.

5 Conclusion

In the teaching of mechanical drawing theory course, introducing the experimental teaching of CATIA 3D drawing software and effectively integrating the two together can not only enrich the classroom content and active teaching atmosphere, but also help the understanding of theoretical knowledge and provide convenience for the cultivation of future talents.